Modelling of radiative power exhaust by sputtered and seeded impurities in fusion reactors with carbon and molybdenum target plates

Abstract

Argon and neon seeded ITER discharges are numerically simulated by coupling a 1D multifluid model for the plasma core with a 2D model for the SOL-divertor region. The model is fully self-consistent with respect to both the effects of impurities on the α-power level and the interaction between seeded and intrinsic impurities. This interaction leads to a significant change in the intrinsic impurity fluxes, and it is found to be essential for a correct evaluation of the average power to the target plates. Even though carbon and tungsten are the real candidates for the ITER target plates, we have compared carbon and molybdenum plates for two ITER inductive scenarios, due to the uncertainties in the tungsten atomic data. In general, the integrated edge-core scenarios with impurity seeding are more favourable in the case of carbon than of molybdenum plates. However, a high density/low confinement scenario with Ne seeding is found for which the requirements in terms of power to the plate and of power through the separatrix are also fulfilled in the case of Mo. The interplay mechanism among different impurities also holds for He ash resulting in a rather weak dependence of the power amplification factor on He confinement.

Edge plasma physics issues for the Fusion Advanced Studies Torus (FAST) in reactor relevant conditions

“…The COREDIV code has been recently applied to simulate nitrogen and neon seeded JET discharges and good agreement with the experimental data has been found [21,22]. The effect of injected impurities on the ITER plasma parameters was also treated by COREDIV simulations [23]. The main limitations of our modelling refer to the lack of pedestals, to the missing drift effects and to the absence of the impurity anomalous pinch.…”

Simulations with the COREDIV code of DEMO discharges

“…Such a neutral model has been successfully used for a number of simulations of the boundary plasma in limiter tokamaks such as TEXTOR [17][18][19], FTU [20,21] and Tore-Supra [22], proving to be able to describe in a reasonable way experimental situations. The same neutral model has also been applied to studies of plasmas in the ITER reactor [23,24]. It takes into account the plasma (deuterium and seeded impurities) recycling in the divertor as well as the sputtering processes at the target plates including deuterium/tritium sputtering, self-sputtering and sputtering due to seeded impurities.…”

Simulation with the COREDIV code of nitrogen-seeded H-mode discharges at JET

“…In contrast with previous simulations, in the actual model of COREDIV the radial impurity transport is described by the simple and widely used analytical expression (4) where G z is the flux of impurities of charge Z, D ⊥ is the anomalous perpendicular main ion diffusivity, n z is the impurity density and S ~ t E…”

“…The coupled core-edge code COREDIV [1,2] has been developed and benchmarked against JET discharges proving its capability of reproducing -with the diagnostic and modeling uncertainties -the main features of JET seeded plasmas [3]. Although global parameters as the electron temperature and density profiles in the plasma core, the total radiated power, Prad, and the ionic effective charge, Z eff , of a variety of JET discharges were well reproduced with the COREDIV model -on this basis a preliminary extrapolation to ITER has been performed [4] -some aspects of the edge model of COREDIV were not fully developed and exhaustively tested, so far.…”